Abstract. Tian et al. (2007) found that the MJO-related total column ozone (O3)
anomalies of 10 DU (peak-to-trough) are mainly evident over the subtropics
and dynamically driven by the vertical movement of the subtropical tropopause
layer. It was then hypothesized that the subtropical total column O3
anomalies are primarily associated with the O3 variability in the
stratosphere rather the troposphere. In this paper, we investigate the
vertical structure of MJO-related subtropical O3 variations using the
vertical O3 profiles from the Aura Microwave Limb Sounder (MLS) and
Tropospheric Emission Spectrometer (TES), as well as in-situ measurements by
the Southern Hemisphere Additional Ozonesondes (SHADOZ) project. Our analysis
indicates that the subtropical O3 anomalies maximize approximately in
the lower stratosphere (60–100 hPa). Furthermore, the spatial-temporal
patterns of the subtropical O3 anomalies in the lower stratosphere are
very similar to that of the total column. In particular, they are both
dynamically driven by the vertical movement of subtropical tropopause. The
subtropical partial O3 column anomalies between 30–200 hPa accounts
for more than 50 % of the total O3 column anomalies. TES measurements
show that at most 27 % of the total O3 column anomalies are
contributed by the tropospheric components. This indicates that the
subtropical total column O3 anomalies are mostly from the O3
anomalies in the lower stratosphere, which supports the hypothesis of Tian et
al. (2007). The strong connection between the intraseasonal subtropical
stratospheric O3 variations and the MJO implies that the stratospheric
O3 variations may be predictable with similar lead times over the
subtropics. Future work could involve a similar study or an O3 budget
analysis using a sophisticated chemical transport model in the
near-equatorial regions where the observed MJO signals of total column
O3 are weak.